The present invention relates to a semiconductor photodetector using a compound semiconductor and a method of fabricating such a semiconductor photodetector.
The prior art has been discussed in the IEEE Journal of Quantum Electronics, Vol. QE-20, No. 3 (1984), pp. 256-264. A semiconductor photodetector disclosed by this article is fabricated in such a manner that Zn is diffused into a circular surface region of an n-InP layer having a relatively large diameter and Zn is thereafter diffused again with a relatively deep thickness from the circular surface region into the inside thereof so as to provide a pn junction which has a step-like difference in depth between an outer peripheral portion of the pn junction and a central portion thereof.
Another type of semiconductor photodetector has been disclosed by, for example, JP-B-61-38871.